Requirements for using a user-defined class in STL

I am trying to use a class that I created with std::list, but VC++ gives me errors such as:
error C2679: binary '=' : no operator defined which takes a right-hand operand of type 'class std::list<struct my_struct,class std::allocator<struct my_struct> >::const_iterator' (or there is no acceptable conversion)

The same error for !=.

So I'm assuming that my_struct needs something so that I can use it with STL. I know that a constructor, copy constructor, assignment, and bool operators == and < are necessary. Is there anything else? I can't remember where I found it the first time and I can't search the boards for some strange reason. :rolleyes:
Any help or a url is appreciated.

If you'd post some code we could take a look at it for you.

You have to define = operator for you struct.

That's the beuty of C++ and the STL - if it doesn't compile, you missed a requirement. look at your compiler output, and correct your class accordingly.

Maybe you should use * before the iterator, e.g.

mylist::value_type value;
for (mylist::const_iterator i = list.begin(); i != mylist.end(); ++i)
{
value = i;//Error of your type
if (value != i) //same error
{//.....
}
value = *i; //Correct if you have a propper copy constructor
// (or default one if possible)
}

I just wanted someone to post the requirements for using a user-defined class in a STL class so I could fix my problem. I'm pretty positive I'm missing something, I just don't know what it is. If anybody knows all of these requirements (I listed a few I knew in my initial post), _please_ post them! Thanks...


-Joe

Ok, found the site that lists the requirements if anyone's interested:
http://www.msoe.edu/eecs/cese/resources/stl/objreq.htm

:confused:
And the offending code that produced all of the error messages in my first message at the locations with "<---":

std::list <my_struct>::iterator dp;
dp = c.affects.begin(); <---

while(!affects.empty()) affects.pop_front();

while(dp!=c.affects.end()) <---
...

This is in a member function (operator =) for a class that contains a variable of type std::list <my_struct> named affects.
my_struct is a struct with a default constructor, copy constructor, destructor, operator =, operator ==, and operator <.
If anybody can help (or needs clarification before he or she can) please let me know. I would be eternally grateful because I don't know what is going wrong here!

If you posted the compiler error - it was a great help.

My guess is that maybe c or c.affects are const, and therefor, their iterator is const_iterator.

But please send the exact compiler error (and compiler type) and I'll try to see if I can see the problem.

Shmulik you were right on the button! I thought people had forgotten about this thread. I had actually tried what you had suggested after inspecting the error message more carefully. I had to replace the ::iterator with ::const_iterator. I wonder if that's just because it was in a member function referring to a member of that class (affects, in this case). Well, anyways, thanks!



-Joe